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Precision Mechanical Structure for High Accuracy High Power E-Beam Drilling/Machining Applications

IP.com Disclosure Number: IPCOM000112590D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 93K

Publishing Venue

IBM

Related People

Grant, WT: AUTHOR [+4]

Abstract

Described is a hardware implementation to provide a high-powered electron beam (E-Beam) drilling system structure that allows high-speed accuracy drilling of many types of substrates, as used in the fabrication of semiconductor devices. This is accomplished by programming rather than changing drill bits or other fixtures. The design provides a reinforced vacuum processing chamber and a precision three-point support structure for workpieces.

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Precision Mechanical Structure for High Accuracy High Power E-Beam
Drilling/Machining Applications

      Described is a hardware implementation to provide a
high-powered electron beam (E-Beam) drilling system  structure that
allows high-speed accuracy drilling of many types of substrates, as
used in the fabrication of semiconductor devices.  This is
accomplished by programming rather than changing drill bits or other
fixtures.  The design provides a reinforced vacuum processing chamber
and a precision three-point support structure for workpieces.

      In high power E-Beam drilling applications, large vacuum
process chambers are used to handle large workpieces.  Due to the
large surface area of the vacuum chamber and the tremendous pressure
difference generated before and after pumping down, the chamber walls
can experience significant deformation.  In general drilling and
welding applications where accuracy is not stringent, such
deformations can be tolerated.

      In precision green sheet machining, such as high density
Multilayer Ceramic (MLC) products built for high performance
computers, high pattern positioning accuracy is required.  In prior
art, the mechanical strength of the chamber was  weakened by having
solid walls only at the bottom side of the chamber.  Two vertical
sides were open for the installation of chamber access doors which
were hung on rails that were attached to the chamber.  These doors
did not provide mechanical support to the overall vacuum chamber.
The chamber's mechanical strength was further weakened by having
large diameter holes in the remaining three sides of the chamber for
mounting the E-Beam column on the top side; and for providing a
pumping path to the vacuum system, and a view port to the chamber on
the remaining two vertical sides.  Significant chamber deformation,
approximately 900 mum was exerted and such non-repeatable deformation
led to errors in E-Beam focusing distance and in E-Beam deflection.
This resulted in defetive green sheets.  In addition, chamber
deformation, such as any non-flatness across the XY travel range of
the workpiece, would result in further focusing and deflection
errors.  The workpiece had to rest on a plane that was flat across
the XY stage travel range in order to contain t...